Machinery such as table saws, band saws, jointers, shapers, planers, sanders, and the like should be stationary during use. In many cases, this type of machinery is permanently installed at a predetermined location in a shop. Such machinery is thus commonly sold with a stationary base having feet that frictionally engage the floor to maintain the machinery at the predetermined location.
But in many situations it is desirable to move this type of machinery between uses. For example, a user may have limited shop space, and may want to store the machinery at a relatively inaccessible location when not in use and then, immediately prior to use, move the machinery to a more accessible location. Or the user may wish to use the machinery at a job site. In this case, movement of the machinery from one location to another at the job site may be desirable.
Accordingly, mobile machine bases are often sold as an accessory to replace the stationary bases originally sold with shop machinery. Mobile bases further comprise a locking system that allows the machinery to be rolled from one location to another between uses yet immobilizes the machinery during use.
More specifically, conventional mobile machine bases comprise a relatively rigid frame assembly to which a plurality of wheel assemblies are attached. The stationary base is removed from the bottom of the machine, and the bottom of the machine is then bolted or otherwise rigidly attached to the frame assembly. Usually, the locking system employs a lock member that moves between a locked position and an unlocked position. When in the locked position, the lock member immobilizes the machinery by frictionally engaging either the wheels or the floor surface to substantially prevent relative movement between the frame assembly and the floor surface. When in the unlocked position, the lock member does not inhibit movement of the frame assembly relative to the floor surface.
Machinery of the type rendered movable by the mobile machine base of the present invention exists in a variety of shapes, sizes, and weights. Currently, manufacturers sell the mobile machine bases in a variety of configurations; the user selects one of these base configurations as appropriate for a given machine configuration.
What will be referred to herein as the "effective footprint" of the machine determines which base configuration should be selected. The effective footprint is normally defined as the outside width and depth dimensions of the bottom of the machinery. The configuration of the mobile base is defined by similar width and depth dimensions that should be just slightly larger than the width and depth dimensions of the effective footprint.
Requiring a base configuration for each effective footprint mandates a production and distribution system in which the manufacturer must design, build, and keep in inventory a plurality of base configurations. The retailers must similarly keep in stock at least the most popular, and preferably all, of these configurations. And the retailer's representative must have some expertise to advise the customer on the right base configuration for a required effective footprint. The result is an inefficient system that is labor and capital intensive. Even then, it would be difficult to provide machine bases for all machines on the market. The need thus exists for a single machine base configuration that can accommodate a number of effective footprints.
Another drawback of conventional machine bases is the locking system used. Some of these locking systems employ a lock member that, in the locked position, bears directly on the wheel to prevent rotation of the wheel. This causes excessive wear on the wheel. Other locking systems require tools to operate the locking system. The need thus exists for a machine base having improved locking systems that do not cause excessive wheel wear or require tools to operate.
Conventional machine bases further employ rigid frame assemblies that cause the machine base to occupy a relatively large volume during transportation and storage. The need thus exists for a machine base that occupies a smaller volume when not in use.